Time change mechanism for clocks



Oct. 29, 1968 c. E. M MAHILL ,4

TIME CHANGE MECHANISM FOR CLOCKS Filed July 24, 1967 F/IGUREI/ FIGURE 2 I ATTORNEY.

United States Patent O 3,407,591 TIME CHANGE MECHANISM FOR CLOCKS Clark E. McMahill, 209 Abbot St., Richland, Wash. 99352 Filed July 24, 1967, Ser. No. 655,414 5 Claims. (Cl. 5885.5)

ABSTRACT OF THE DISCLOSURE An automatic setting mechanism to indicate change between standard and daylight saving times in the normal clock by moving a lever between two possible predetermined limiting positions. The hour hand drive shaft is split with first gearing provided on the adjacent split edges and second satellite pinion type gearing communicating between the first gearing members to form a motion train. A lever communicating externally of the clock case pivotably communicates with the second gearing and is moveable between two terminal points to move the hour hand one hour or thirty degrees of angular distance.

BACKGROUND OF INVENTION Related applications There are no applications related hereto filed in this or any foreign country.

Field of invention This invention relates generally to the field of horology and more particularly to a mechanism that permits changing between daylight saving and standard time by the motion of a single lever between two extreme positions.

Description of prior art Heretofore it has become known to provide various mechanisms to semi-automatically change indicated clock time to correspond with a radical change in time, usually as occasioned by a change from standard to daylight saving time or a change from one time zone to another. In general the devices known to accomplish this purpose have involved a mechanism associated with the scalar face of a time piece, to cause its motion, or have involved an immoveable multiple scale or a rotarily moveable partial scale.

Scalar devices associated with the clock face to accomplish this function indicate only the correct hour by interpretation of a scale or the relationship between the two scales, which oftentimes is complex for the average user and leads to a high possibility of error. Various devices that have rotated the clock face relative to the hands have found problems in that the minute hand will not indicate the correct time, being an angular distance, usually of thirty degrees or five minutes in time, ahead or behind the proper time after the completion of the operation, depending upon the direction of the change, unless complex ancillary gearing be provided.

The instant invention differs from this art in that the hour hand is rotated an appropriate amount to indicate the time change by ancillary gearing structure moveable by an associated lever between two extreme limiting positions marked to indicate the time being shown by the clock.

SUMMARY OF INVENTION The instant invention was conceived to provide a semiautomatic time changing mechanism that accomplishes its function with motion of one lever between two possible positions to cause a clock to indicate correct time after the change, no matter in which direction it may be.

This function is accomplished in a normal clock structure having independently rotatable, axially coincident ice concentric inner second hand, medial minute hand and outer hour hand shafts, by splitting the hour hand shaft, preferably rearward of the clock face, and providing cooperating spaced internal and external gears on the opposed split shaft faces. Paired opposed pinion gears communicate between the hour hand shaft gears providing a one to one ratio to allow normal hour hand motion. These pinion gears are carried on a pinion shaft rotatably mounted on one arm of a bell crank having its center pivotably mounted, preferably on the minute hand drive shafts, but in any event for pivotably motion about the axis thereof. The outer arm of this bell crank extends without the clock case through an orifice providing two extreme limiting positions for the lever, each fifteen degrees apart from the other. The clockwise-most limiting position is usually designated as daylight saving time and the other as standard time so a user cannot be confused in any time changehe merely has to'move the lever to the appropriately designated time he desires.

In providing such a structure it is:

A principal object of my invention to provide a simple time change mechanism requiring only manipulation of a single lever between two marked limiting positions to avoid or reduce to a minimum any possible user confuson.

A further object of my invention to provide such a mechanism that is so constituted that after manipulation it will allow the clock to show correct time as to hour, minute and second.

A still further object of my invention to provide such a device that is of new and novel design, of sturdy and durable nature, of simple and economic manufacture and one that is otherwise well adapted to the uses and purposes for which it is intended.

Other and further objects of my invention will appear from the following specification and accompanying drawings which form a part of this application. In carrying out the objects of my invention, however, it is to be understood that its essential features are susceptible of change in design and structural arrangement with only one preferred practical embodiment being illustrated in the accompanying drawings, as required.

BRIEF DESCRIPTION OF DRAWINGS In the accompanying drawings, wherein like numbers of reference refer to similar parts throughout:

FIGURE 1 is an orthographic front view of a typical wall mounted clock, embodying my invention.

FIGURE 2 is an orthographic side view of the same clock illustrated in FIGURE 1 showing the time change lever and its relationship with the clock casement.

FIGURE 3 is an enlarged vertical orthographic side view of the gearing mechanism of my invention associated (with the hour hand of the clock, showing its nature in etail.

FIGURE 4 is an orthographic rearward-looking view of the same mechanism illustrated in FIGURE 3 taken on the line 4-4 thereon, showing various parts of the gearing, their configuration and relationship from this aspect.

FIGURE 5 is an enlarged isometric view of the time change lever fastening mechanism.

DESCRIPTION OF THE PRE ERRED EMBODIMENT Referring now to the drawings in more detail, there will be seen an ordinary wall hung clock, including case 10 and viewing window 11 enclosing operative mechanism 12 and time change mechanism 13 associated with the band structure 14.

, The nature of clock case 10 is not critical, so long as it be sufficiently rigid to serve its encasement purpose and be of substantially circular shape or else have a substantially circular peripheral area to accommodate the setting lever and allow it to move relative the case as hereinafter required. The case mounts viewing 'WindOW -11, wherethrough the clock scale and hands may be seen from a forward position, by means of an annular mould releasably joining the two members. This structure is common in many blocks of commerce.

Operative mechanism 12 is immoveably carried within casement 16 with associated clock setting stem 17 projecting therefrom. The particular nature of operative mechanism 12 is not material to my invention and it will function equally well with any of the various movements commonly used in clocks.

Time change mechanism 13 provides outwardly extend ing time change bell-crank 18 with change arm 21 carrying at its peripheral end fastening lever block 19 slideably mounting fastening lever 20 for motion perpendicular to the plane of the bell-crank. Preferably the fit between lever 20 and carrying block 19 is such as to require some force to overcome the friction therebetween or else the lever should be biased to a forward position (with reference to the clock) by mechanical means such as a spring (not shown).

An appropriate time change lever slot is provided in a peripheral part of case 10 to accommodate the outwardly projecting time change arm fastening lever. This slot has a radial length of some fifteen degrees of angular measure to allow corresponding motion of the hour hand of thirty degrees or one hour of time. At the limits of angular motion of the slot there are provided paired opposed forwardly extending (with reference to the clock) nitches 26 to accommodate fastening lever 20- and maintain it in an appropriate limiting position. With this structure then, the angular position of bell-crank 18 may be changed fifteen degrees with reference to case 10 and may be maintained in this position by moving time change lever 20 forwardly into the appropriate holding nitch 26.

Clock face 27 is of the ordinary commercial variety commonly used in such mechanisms; it is fixedly mounted on the inner surface of case 1-0 by means of plural face mounting protuberances 28. The face is preferably marked in terms of hours and minutes in the normal fashion and has a central hole to allow projecting of the compound hand axles forwardly therethrough from the rearwardly positioned operative mechanism 12.

Referring now particularly to the drawings of FIG- URES 3 and 4, the gearing mechanism of my invention is seen. It is here to be noted that in the normal clock mechanism a compound shaft protrudes forwardly through clock face '27, this shaft having an innermost second hand axle 29, a hollow axially aligned minute hand axle 30 rotatable thereabout and another hollow axially aligned hour hand axle 31 rotatable about the minute hand axle. The hour hand 32 is positioned on the outwardmost extension of hour hand axle 31, generally by frictional engagement therewith, forwardly of face 27, as in the normal clock structure. Forwardly of the hour hand is minute hand 39 irrotatably carried upon the forwardmost extension of minute hand axle 30, again generally by frictional engagement therewith, and forwardly of the forwardmost extension of minute hand axle 30 is the forwardmost projection of second hand axle 29, again releaseably carrying second hand 40. This second hand may or may not be included in a clock mechanism; it has no particular function in regard my invention, but would in any event indicate the correct time after a change.

My time change mechanism requires removal of a portion of hour hand axle 31 immediately rearward of clock face 27 to leave a forward independent axle portion 31!: and a rearward driven portion 31b. Rearward axle portion 31b irrotatably mounts forward facing internal gear 33 and forward portion 31:: irrotatably mounts external gear 34 at a spaced distance forwardly of gear 33 suflicient to allow pinion type gearing to communicate between the hour axle gears. The normal clock structure provides suflicient space between the operative mechanism and the face for this structure. The number of teeth in gears 33 and 34 is the same.

Paired opposed similar pinion gears, irrotatably carried at the ends of pinion shaft 37, communicate between the hour axle gears with rearward pinion 35 enmeshed in internal gear 33 and forward pinion 36 enmeshed with external gear 34. The pinions have the same number of teeth to cooperate in providing an identical norm-a1 rotary motion between fonward hour shaft 31a and rearward driven shaft 31b during normal clock operation.

Time change bell-crank 18 includes central body 23 structurally communicating between pinion arm 22 and change arm 21, communicating as aforesaid externally of the clock casement for manipulation. The body is rotatably mounted on minute axle 30 by journal 24. Pinion arm 22 rotatably mounts the central portion of pinion shaft 37 by journal 38.

Having thusly described the structure of my invention, its operation can now be understood.

Firstly, a horological structure is constructed according to principles well known in the art and conformed to the foregoing specification to include the mechanism of my invention. The structure illustrated in FIGURE 2 would indicate a clock in standard time position, that is, with time change lever 20 in position A. To change this clock to daylight time, it is merely necessary to move time change lever 20 clockwise to position B and the clock will automatically show the correct daylight time immediately after such operation.

To analyze this motion more completely, it is tobe noted that angular motion of time change arm 21 of bell-crank 18 will cause a corresponding angular motion of pinion arm 22 and thusly angular motion of pinion shaft 37 about the minute hand axle and relative the clock works. This motion will cause a corresponding double angular motion of the hour hand as the driven portion 31b of the hour hand will remain stationary and the forward independent portion 31a will be moved, since both similar pinions 35, 36 are enmeshed with the similar hour axle gears 33, 34, but one of the latter gears is internal and the other external. During the operation no motion of the minute or second hands will result and the correct time will therefore be shown after the operation.

It is to be noted that the normal time keeping motion of the clock will not be interrupted during any change operation.

It is further to be noted, that during ordinary running operations, the pinion shaft will rotate to allow normal motion of the hour hand, since the motion of internal gear 33 will be transmitted to external gear 34 by the pinion structure.

The foregoing description of my invention is necessarily of a detailed nature so that a specific embodiment of it might be set forth, as required, but it is to be understood that various modifications of'detail, rearrangement and multiplication of parts may be resorted to without departing from its spirit, essence or scope.

Having thusly described my invention, what I desire to protect by Letters Patent, and

What I claim is:

1. In a clock having a casement carrying rearward operative mechanism and a forward face with a compound hand activating axle communicating from the operative mechanism forwardly of the face to indicating hands cooperating therewith, with at least an inner minute hand axle and an outer hour hand axle independently rotatable thereabout, a time change mechanism associated therewith, comprising, in combination:

a split hour hand axle having a section removed between clock face and operative mechanism;

first gearing means communicating with the adjacent edges of the split hour hand axle;

second gearing means, communicating between said first gearing means, adapted to communicate the same rotary motion of the driving hour axle to the separated driven hour axle; and

means of moving said second gearing means a pre determined angular distance about the compound hand axles as a center to change the rotary position of the hour hand.

2. The invention of claim 1 wherein said first gearing means is further characterized by paired opposed internal and external gears, having the same number of teeth, irrotatably carried by adjacent edges of said split hour hand axle.

3. The invention of claim 1 wherein said second gearing means is further characterized by paired opposed pinion gears having the same number of teeth and being irrotatably carried upon a common axle.

4. The invention of claim 1 wherein the means of angularly moving the second gearing means is further characterized by a bell-crank with central body rotatably carried by the minute hand axle between the adjacent ends of the hour hand axle for motion in a plane substantially perpendicular thereto and with one pinion arm rotatably communicating with the second gearing means and one change arm communicating externally of the clock casement for manipulation between predetermined angular positions.

5. In a clock having a casement carrying rearward operative mechanism and a forward face with a compound hand activating axle communicating from the op erative mechanism forwardly of the face to indicating hands cooperating therewith, with at least an inner minute hand axle and an outer hour hand axle independently rotatable thereabout, a time change mechanism associated therewith, comprising, in combination:

a separated hour hand axle exposing the inner minute hand axle for a spaced distance between clock face and operative mechanism;

paired opposed cooperating axle gears, each having the same number of teeth, irrotatably carried by the adjacent surfaces of the hour axle elements, one of said gears being an internal gear and the other an external gear;

paired opposed cooperating pinion gears communicating between the axle gears, each having the same number of teeth and being irrotatably carried on a common shaft to transmit the same rotary motion of the driving hour hand shaft to the driven portion thereof;

a bell-crank having a body rotatably carried by the minute axle between the paired opposed axle gears for motion in a plane substantially perpendicular to the minute hand axle, said bell-crank having a pinion arm rotatably journaling the pinion axle carrying aforesaid paired pinion gears and a change arm communicating externally of the clock casement for manipulation between predetermined angular positions to change the angular position of said pinion axle relative the minute hand axle to change the hour hand position relative the face; and

means of releasably maintaining the change arm in predetermined angular position.

References Cited UNITED STATES PATENTS 1,393,569 10/1921 Richardson 58-126 1,925,288 9/1933 Spranger 58-126 2,251,021 7/1941 Nebergall 58126 2,662,368 12/1953 Glenn 5843 2,674,085 4/1954 Israel 5885.5 2,777,281 1/1957 Berry 5885.5 2,995,888 7/1961 Ryan 5885.5 3,358,437 12/1967 Burg 5885.5 X

RICHARD B. WILKINSON, Primary Examiner.

STANLEY A. WAL, Assistant Examiner. 

